Diamagnetic separation.



No. 653,342. Patented July l0, I900 E. GATES.

DIAMAGNETIC SEPARATION.

(Application flled Sept. 26, 1899.1 (No Model.) 2 Sheets-Sheet l,

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No. 653,342. Patented luly- I0, 1900. E. GATES.

DIAMAGNETIC SEPARATION.

(Application filed Sept. 28, 1899.!

2 Sheets-Sheet 2,

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UNITED STATES PATENT ()FFiICE.

ELMER GATES, OF CHEVY CHASE," MARYLAND, ASSIGNOR TO THEODORE J,

MAYER, OF WASHINGTON,

DIAMAGNETlC SPECIFICATION: forming part of Letters Application tiled September as. 1 899.

To all whom it may concern:

Be it known that I, Emma Guns, acitizen of the United States, residingat Chevy Chase, county of Montgomery, State of Maryland,

' have invented certain newand useful Improvements in Diamagnetic Separation; and

do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to to which it appertaius to make and use the same.

My invention relates to certain new and useful improvements in the separation of diarnaguetie substances from mixtures in which .15 said substances appear, and more particularlyto the separation from each other of diamagnetic substances of varying susceptibility-as, for instance, gold or silver from sand,

quartz, and the like.

The invention is based upon the principle that whereas paramagnetic substancessuch as iron, nickel, and cobalt-tend td move from weaker portions of a magnetic field'to ward the stronger portions dianiagnetic sub- 2 5 stances tend to move from the stronger portions of the magnetic field toward weaker portions. The repellent force thus exerted is, however, extremely moderate in comparison to the force of attraction exerted upon 0 paramagnetic substances by a magnetic field of a given intensity,and, so far as I am aware,

the employment of diamagnetic action for the successful separation of substances'has not heretofore been regarded as feasible.

In practicing my invention the mixture of substances to be separated, if it does not originally occur in the form of finely-subdivided particles-as, for instance, sea-sand having free gold in the form of fine particles o distributed throughout its massis brought into that condition by means of stamps or crushers.

The characteristic feature of the invention consists in feeding the mixture of finely-di- 4 5 vided particles into an intense part of a mag netic field and causing the particles of greater diamagnetic susceptibility to travel toward a weaker part of the field bycontinual progression, detaining or continuing them within 0 and subjecting them to the action of the lines 4 of force until the more diamagnetic particles DISTRICT OF COLUMBIA.

SEPARATION.

Patent No. 653,342, dated July 10, 1900;

Serial No. mass. on imam.)

have been so far diverted fromthe less diamagnetic particles asto be capable of being received and collected separately. By the expedient of prolonging the period within which the mixture is subjected to the action of the magnetic field I find thata comparatively-slight initial tendency to separate is by progressive small increments finally sufficient to effect the complete separation of particles of one degree of diamagneticsusceptibility, such as gold, from particles of another degree of diamaguetic susceptibility-as, for instance, sand or crushed quartz.- In fact, I have found, for instance, that the tendency of fine particles of gold to move from the strongest to the weakest part of a magnetic field is so much greater than the.more feeble tendency of very weakly diamagnetic substances, such as sand, to move in the same direction that when a mixture of the particles free to move with 'respect to each other is, as above described, detained or continued in and subjected to the action of the magnetic field for a sufficient period the separation is readily effected and with a moderate expenditure of electric energy. The desired freedom of motion of theparticles within the magnetic field, as also their sufiicient period of detention therein, may be readily obtained in various waysas, for instance, by causing them to drop by gravity through a magnetic field or succession of magnetic fields of considerable height, orby causing them to pass more slowly through a magnetic field of less height, which may be effected by immersing the magnetic polepieces within a body of water or like liquid, through which the particles will sink more slowly than through the air, or by causing 0 the particles to roll down the surface of an inclined plane located in the field, or'by placing the particles upon a thin disk or plate arranged horizontally or substantially horizontally within the field and imparting to the disk or plate such vibrations as will agitate the particles, whereupon they will arrange themselves in accordance with their varying degrees of diamagnetic susceptibility.

In the accompanying drawings I have represented the preferred type of apparatus for the practice of myinvention.

Figure 1 represents a top plan view of said apparatus, omitting the feeding-hopper; and Fig. 2 represents a front elevation of the apparatus, showing said hopper.

Similar letters of reference indicate similar parts in both views.

Referring to the drawings, the apparatus herein shown is one wherein a highly-concentrated field of force is obtained by causing the magnetic lines to pass between polepieces F, having pointed or reduced ends f. These pole-pieces form the terminals of cores G, connected by a yoke H and enveloped by the coils or bobbins J. In practice it will be desirable with a current of fifty amperes and five hundred volts and with bobbins having each four hundred thousand ampere-turns of No. 6 Brown Jr Sharpe donblecotton-covered wire to employ cylindrical cores each eighty inches in length and ten inches in diameter connected by arectangular yoke of four times the cross-section of one of the cores. The pole-pieces F mayjconveniently be extended laterally, so as-to increase the length of the field, or I may employa plurality of magnetsas, for instance, two magnets of the type shown-arranged one above the other in such manner that their interpolar spaces shall constitute a continuous passage for the falling bodyof material to be separated. The placersand, crushed quartz, or other material to be separated is fed into the intense magnetic field existing between the pointed ends of the pole-pieces from a hopper or supply-receptacle K, and in their descent the particles of gold or silver move out laterally from the falling column into the less intense field existing between the slanting or inclined sides of the pole-pieces. Consequently the particles of gold or silver may be separately collected as heads of more or less complete concentration in the outer receiving-hopper .L', whereas the main body portion of sand, deprived of its gold and silver, is collected, for instance, in the central receptacle M.

Having thus described my invention,what I claim is The method of separating diamagnetic particles from a mixture containing them, which consists in feeding the mixture into a relatively-intense part of a magnetic field, con-.

tinuing it in and subjecting it to the action of the magnetic field until the diamagnetic particles to be separated have gradually moved out from the mixture into a relativelyweak part of the field, and then collecting said particles separately as heads, substantially as described.

In testimony whereof I afiix my signature in presence of two witnesses.

ELMER GATES. Witnesses:

EDWIN S. CLARKSON. JOHN C. Pmmm. 

